| The atomic force microscope (AFM) is used as a tool to investigate architecturally-driven differences in machining behavior of polymers having the exact chemical composition and similar molecular weights, but different three-dimensional connectivity and spatial orientation. A novel machining protocol was developed for probing the machining behavior of ultrathin films of the target polymers. The bases for the qualitative and quantitative analyses of the machining experiments, on the polymeric architectures, is investigated, developed, and delineated. This included identification of and adjustments for experimental and environmental factors that influenced experimental results. Quantitative analysis required the development of a unique mathematical approach, which resulted in the development of computer-based routines as tools to facilitate extraction of surface roughness data. Subsequent analyses of these data resulted in plots from which the characteristic machining behavior of the two polymer architectures, including the extrapolation of values such as coefficients of friction and the work of machining, could be compared and contrasted. Though these numerical results cannot yet be considered robust, the further, rigorous development of the protocol and these tools may provide a basis for micro-and nano-scale conclusions, which can be extrapolated to the macroscopic scale. These studies identified molecular weight driven differences in machining behavior within a family, as well as distinct differences between the architectural classes of polymers.; These investigations required the syntheses of dendritic and linear homologues. Generation four, five and six poly(benzyl ether) dendrimers were synthesized according to published procedures.{09}Compositionally equivalent linear poly(benzyl ether) analogs were prepared by a novel "one-pot" synthetic approach, using silicon-assisted etherification chemistry. The impact of isomeric polymer forms, in particular, the effects of "perfect" branching, on machining behavior, and, hence on mechanical properties, was then determined. Experiments were conducted utilizing the "contact mode" proximal probe technique to machine ultrathin polymer films spin-cast on graphite substrates. The study highlights the experimental and material factors that must be addressed, and develops a foundation for further studies. |
